Category Archives: Structures

This weekend I found myself in the centre of Birmingham, and we happen to pass by Waterstones book shop to the rear of new Street, its being hacked about to make way for the new reail station and tram system. But what caught my attension was the way the lower ground floor to the old bank building, now a waterstones, had been exposed, to reveail the old sign I can only think that the planners would, quite rightly, have been all over this, I went into the store to purchase a new Michelin guide for France, and the very helpfull chap told me, they arer recording the information and it will be carefully covered over, and left in place.

Excellent I thought, as I looked at it, but then I started to look at the support structure and the Steel Beam support held up by what looks like cast iron pillars. The beam is a plted and ribbed stell section, not so often seen these days, my father, a steel engineer, said most engineers might not know how to detail this correctly, so I took some time to take a few photos and record the detail

I wonder how good the steel is, from the distance I was able to view it, I wonder how far rust has eaten into the beam, but looking at it, I thought it just needed cleaning and painting.

Still an interesting detail now exposed for a short time, and if your in the area, well worht a visit to see it for your self. in fact the whole area is worth a visit as the station is being reconstructed, I almost said refurbed, its not, it being reconstructed, take a look at the new stainless steel facade, the reflection is interesting, can’t say I like it and I wonder if the sun path has been looked at.

I have more photos in my Flickr account, take a look by clicking on todays photo

Some time back I mentioned that a group of students had worked out a rather neet way to provide the structure for small developments, via the cutting of ply panels, to form whats now known as the Wiki House.

Well it’s not gone away and they have done a little nore work on the design and added some more plans. Its all in Sketchup, so easy to view, I actually imported them into Vectorworks, and viewd then there as well.

I like this type of research, the structure is very interesting and uses so little in terms of manufacturing, any one can print of these sheets, the different sections needed are laid out for a large sheet of ply, so it could not be easier, fitting then together might need a little training, but a couple of youtube videos would be good for this. Existing videos show the basics and well worth watching,.

Simply each frame is made up of two ply layers, the panels of one layer offset from the other so the joints are always covered by the other, hence the ability to make the spans they can. Simple joints and ply pins joint and pull the frames together, in a process thats well understood of you ever look at old timber frame structures.

The videos below are just two of many on YouTube, that show the simple construction of the Wiki House.

The CPD here is a load of different things, from simple structure, to cutting of ply, to third world housing, to 3D drawing in Sketchup and exporting to Vectorworks.

I was at my grand daughters christening this weekend, and I could not help looking up as the minister went on for a while about welcoming in little Stevie into the church, the walls were bowing out, and not just a little, there was a significant bow to the top portion of the wall. The answer as to why is obvious and I suppose is the CPD of this article, take a look at the photo I took, shows the roof structure is not so well braced, and the slate roof covering was enough to move the walls. Ok so this roof has been like it for 500 years and is not going anywhere.

but the real CPD is not the bowing of the roof, but the way our medieval designers worked out how to build, mostly I'm afraid by example and experience, I suspect that little or no calcs were done, or that the designer even new what this statement even meant.

Risks were taken, and sometime they worked, but so often they did not and building fell down, or repairs were made to stop walls spreading. Steel ties were added, or buttresses build on the exterior. The picture I took, does not clearly show the bow, but it was there, the roof structure is just about visible, try downloading it and zoom in.

If you ever get chance to read Ken Follett's “The pillars of the Earth”, your see what I mean about structure and design.

The secondary CPD is that old adage, observation, for me it was forced upon me by a boring lecture, but so often we walk about with our eyes closed, so this week, the CPD is observation, and walking.

I saw this on my walk round Cambridge yesterday, and it struck me that this was not the way to load up a walkway. Simply, a scaffolder has erected a two story scaffold on a timber walkway, that's in turn supported on a metal framework, embedded into the river.

I looked at it and the timber planks are about 19mm plus, thick, but they bear onto a metal frame. I might have let this go if the scaffold was bearing directly over the metal fame, but it was not, it was bearing on just timber, mid to left span !!!!!.

Would I have bedded direct into the river, no, I would have at least put a sole plate down to spread the load, the contractor might argue that it's just to protect the people walking along the path, whilst they paint, or repair,and no loading would occur, that might be, but it just did not look right. Needless to say, we did not hang about, and left.

Still my walk round Cambridge was well worth the trip, an excellent city with lots to look at, and observe, the gardens, and there are a lot of college gardens the general public, just don't seem to know about are in fine form at the moment, so well worth a visit.

We went into Kings College and paid up to visit the chapel, a very interesting building with an excellent vaulted ceiling, and in one of the side exhibition area a very good model of the construction. Unfortunatly it was behind a glass screen, and lit in such a way, that to get a good picture I had to use a flash, so no picture, as the glare was just to much.

But the explanation of the fan arch ceiling was excellent, I made some notes so will try and write them up later.

I only managed to find one Bench mark on the entrance to one of the college, still a good find.

I last visited Cambridge for the CIAT AGM, so had a good idea where to go, the college garden are excellent, so is the punting, we did not partake, but watched the locals trying to avoid the tourists, excellent fun we thought.

I had a conversation recently regarding the use of timber floor joists, a manufacturer asked why I always specified sawn cut joist, why did I not allow natural un-sawn logs, after all there are loads of old houses that were built with them and they are still working fine.

The simple answer is that un-sawn timber would not fit all the metal joist hangers and I know of no standard I can use to size the timber for span. But I love the idea of using timber like this so I intend to look more closely at the idea.

As an alternative to sawn timber joists, I have been specifying I-joists, the engineered timber joists with a top and bottom string of timber with a ply or similar web, the span tables for these are all over the web. I like these simply because of the span, but sustainably they have to be looked at. Take a look at James &Jones they have a typical spread of products, I have no tie to this company, they just have a good site.

Take a look at the other type of I-joist the ones with metal webs, these allow for greater use of inter floor trunking and air distribution and pipe and cable runs to be hidden away and designed for, with specific access traps, and service trays. The passive house presentation I went to at the begining of the year showed these as standard.

Jon Pickup gave me a set of vectorworks CAD files for these all in different sizes, I realy need to make these up into a 3D format and create a sample beam.

Today's picture shows the underside of an i-joist floor, notice the t&g boarding. s for CPD there has to be a good half hour just following up my blog by looking for these products on the market, most timber mills seem to have a good selection, as for self build, the metal webs opens up a raft of advantages, but be aware of certification, making them up your self might bring problems, but it's an interesting thought.

Simpson Strongtie, have a large range of metal I-joist hangers and details, and again I have no tie, (pun) they just have a good site.

This is one video you have to watch, I was spell bound for the entire video, Miyoko Shida has perfected an amazing act, where she starts with a feather, and balances it on a stick, which in turn is balanced on another stick and so on with about 10 or so other sticks, all equally balanced, but relying on the weight of a feather, you sit in wonder, and finally she removes the feather and all crumble.

There is CPD here, believe it or not, it's structures, a question of balance, each stick is a little longer and has a larger counter balanced end, to react to the weight of all the other sticks and ultimately the feather.

I watched all of them there are 11videos in the set, each not very long, I watched all of them within 40 mins and that's with a break, I then went of to do some research, look at arch pictures and see if I could better the videos, I could not. So with the videos and my research, I think an hour of quality CPD is in order.

So if your a student or seasoned Technologist, please take the time to look through this set of Arch Videos, they are realy well worth it. I tried to watch them on my iPad, but they are a flash set so main computer only.

I have collected a nice set of arch picture on my Flickr account, I have seen as I have travelled, some in stone, some brickwork, some simple door arch's some more complex as vaults, but if you sit and work out how and why as shown in the videos, you can easily work out the structure and lines of force.

Today's picture is of an arch I saw on a recent trip to York, and shows clearly the structure.